factorization -------------------urgent

1.
x^2-y^2+2zx+2yz+2y-2z-1
= x^2 + (-y^2+2y-1) + (2zx+2yz-2z)
= x^2 - (y-1)^2 + z(x+y-1)
= [x^2 - (y-1)^2] + z(x+y-1)
= (x+y-1)(x-y+1) + z(x+y-1)
= (x+y-1)(x-y+z+1)

2.
x(b^2-c^2)+(c^2-x^2)+c(x^2-b^2)
= xb^2 - xc^2 + c^2 - x^2 + cx^2 - cb^2
= b^2(x-c) - (x^2-c^2) + xc(x-c)
= b^2(x-c) - (x-c)(x+c) + xc(x-c)
= (x-c)(b^2-x-c+xc)

3.
x^2(b-c)+b^2(c+x)-c^2(x+b)
= x^2(b-c) + cb^2 + xb^2 - xc^2 - bc^2
= x^2(b-c) + x(b^2-c^2) + bc(b-c)
= x^2(b-c) + x(b-c)(b+c) +bc(b-c)
= (b-c)(x^2+xb+xc+bc)

p.s. in 2nd term, there should be b^2 instead of b2

4.
x^2(y+z)+y^2(z-x)+z^2(y-x)-2xyz
= yx^2 + zx^2 + zy^2 - xy^2 +z^2(y-x) - 2xyz
= z^2(y-x) + z(x^2-2xy+y^2) + xy(x-y)
= z^2(y-x) + z(y-x)^2 - xy(y-x)
= (y-x)[z^2 + z(y-x) - xy]
= (y-x)(z-x)(z+y)

p.s. in 2nd term, there should be z-x instead of z-

1.
(x+y-1)*(x-y+2*z+1)

2.
(x-c)*(c*x-x-c+b^2)

3. (mistake in question, b2 should read b^2
-(c-b)*(x+b)*(x+c)

4. (mistake in question, (z-) should read (z-x)
(y-x)*(z-x)*(z+y)